Rate determining equipment



Filed sept. 2o, 1960 2 Sheets-Sheet 1 A Tron/VE v 2 Sheets-Sheet 2 /Nl/ENTOJ Y By CL. WHEELER ATTORNEY Feb- 25, 1964 c. l.. WHEELER RATE DETERMINING EQUIPMENT Filed Sept. 20. 1960 United States Patent 3,2 ,611 RATE DEEFhdP-NG EQUPli/ENT Cnries L. V/heeier, Betr-nit, Mich., assignor to American telephone and Telegraph Company, New York, NX., a corporation of New York Fitted Sept. 2d, iQti, Ser. No. 57,237 12 Claims. tCi. E70-1S) rl'u'his invention generally relates to telephone switching equipment that automatically determines the rate treatment for customer service and particularly relates to equipment at a centralized call recording and switching center for simplifying the charge rate determining procedures for at rate customer calls.

Flat rate telephone service is oered to customers, such as residential telephone users, for a stipulated monthly charge which covers all calls to other telephone stations within a specified area. This service is often provided in automatic telephone systems because no records of calls completed within the originating flat rate area are required for charging purposes and, as a result, the only automatic call recording equipment that need be provided 1n the local originating office is that necessary to record charge data for calls directed to oces external to the originating flat rate area. As a result, flat rate service frequently reduces the volume of extra charge calls to the point where it is too small to justify economically'the installation of automatic call recording equipment' in many local offices. In such cases, a current practice is to centralize facilities in a tandem oiiice for recording the extra charge call data for a number of such local ofiices. A tandem office of this type is known in the art as a centralized call recording center.

Although the aforementioned practice largely overcomes major economical obstacles, in doing so, it gives rise to a number of technological problems unique to centralized call recording systems. One such problem is the complex equipment arrangements used to handle flat rate and extra charge rate calls from flat rate customers served by local omces which are not equipped with automatic call recording facilities. These arrangements have heretofore required equipment at the individual local ofces to determine the call rate treatment for these customers by screening each of their originated calls to ascertain whether its terminating point is Within or without the fiat rate calling area. As a consequence of this screening, the originating otiice equipment segregates the dat rate and extra charge rate calls and routes them over separate groups of tandem trunks to the centralized call recording center in order to simplify the identification of the cails for which no record is required.

A more desirable arrangement than the foregoing would be to route both of the aforementioned types of calls over the same group of tandem trunks to the call recording center and to utilize facilities at the latter point for automatically determining the appropriate rate treatment. Such an arrangement would eliminate the local oflice screening equipment and would also reduce the amount of route controlling equipment and tandem trunk facilities in the local offices.

Accordingly, a general object of this invention is to simplify the charge rate determining procedures for flat rate customer calls served by centralized call recording systems.

Another object of the invention is to improve centralized call recording systems from the standpoints of equipment economy and efficiency in operation in the serving of calls originated by flat rate customers.

in accordance with the present invention, flat rate customer calls to telephone stations Within and without the flat rate calling area are served by the same incoming trunks at the tandem ofdce functioning as a centralized ECC call recording center, and the latter ofi'ice is adapted to determine automatically the appropriate rate treatment for all calls. in the tandem office, all incoming trunks that serve calls from flat rate customers having identical rate treatments are combined into flat rate trunk groups and are associated with trunk circuits distributed over a plurality of equipment frames. lVhen any one of the trunks is first engaged on a call, the associated trunk circuit is operated to activate equipment that receives the called oflcecode from the originating office and calling customer rate class data from the trunk circuit and then, in response tothe receipt of this information, determines the rate treatment for the call.

An advantage of this invention is that local originating oce equipment not required to segregate flat rate customer traffic into two groups and to route it over separate tandem trunks to a tandem olce. rIliis allows for major economies in the route controlling and trunk circuit equipments in the local oices. A salient advantage of the invention is its usefulness and adaptability to existing centralized call recording systems.

A feature of the invention is the provision of equipment whereby the same incoming trunk group in a tandem office may serve both fiat rate and extra charge rate calls.

Another feature is the provision of equipment in the tandem office for determining automatically the rate treatment for call-s served by the incoming trunk groups serving both ilat rate and extra charge rate calls.

An additional feature is the provision of equipment in a tandem oice for idtentifying the incoming trunk groups serving flat rate and extra charge rate calls for the purpose of ascertaining the terminating offices within and without flat rate calling areas.

Still another feature is the provision of equipment in the tandem oliice for translating the called office code during each incoming call and for determining Whether a dat rate or an extra charge is made for each call.

A further feature includes the provision of facilities for recording charge data for calls in the tandem omce and the circuit means provided for utilizing the recording facilities only for the extra charge calls served by the incoming trunk groups serving both flat rate and extra charge rate calls.

lThe foregoing objects, advantages, and features of the invention, together with others, will be more clearly understood from a consideration of the following description and accompanying drawings.

The telephone system with which the invention is intended to function, by way of example, is disclosed in U.S. Patent 2,848,543, issued August 19, 1958, to R. N. Breed et al. The characteristics and operations of certain apparatus units in the sender, marker connector, and marker circuits of this system are disclosed in the following U.S. patents: 2,235,803, issued March 18, 1941, to W. W. Carpenter, and 2,688,658, issued September 7, 1954, to W. W. Carpenter et al.

Referring to the drawings:

FiG. 1 shows, in block diagram form, equipment of the tandem office serving as a centralized call recording center; and

FG. 2 schematically depicts the rate determining equipment connected in an operative arrangement with apparatus units of the marker and sender circuits.

It will be noted that FIG. 2 employs a type of notation referred to as detached contact in which an X represents a normally open Contact of a relay; normally referring to the unoperated condition of a relay. The principles of this type of notation are described in an article entitled An improved Detached-Contact-Type of Schematic Circuit Drawing, by F. T. Meyer in the September 1955 publication of the American Institute of 3 Electrical Engineers Transactions, Communications and lectronics, volume 20, pages 565-513.

lt is also noted that the invention is particularly concerned withrtheV parts of the incoming trunks, trunk link rame, trunk link connector, marker, marker connector, and sender circuits which are shown on FIG. 2. The other circuit units of the system comprise no part of the present invention and are neither shown nor described in detail herein except in reference to the block diagram of FiG. l. For a complete understanding of the construction of the latter units and of'their operations in performing their functions, it is intended that reference be made to the previously idented patents.

The general'organization of the principal circuit units of the systemwvill now be described with reference to FIG. l. All incoming trunks from local originating oliices terminate in the tandem oice at incoming trunk circuits which appear on trunk link frames. All outgoing trunk circuits andtrunks to terminating oices ap- L ear on oce link frames. Illustrative fo these arrangements are the incoming trunk lTK and trunk circuit ITC associated with the trunk link frame TLFl, and the outgoing trunkv circuit OTC and trunk GTK associated with the trunk link frame GLF. A plurality of'incoming and outgoing trunks and trunk circuits are usually grouped on their respective frames in conformity with the traic requirements. incominfr and outgoing trunks are interconnected by means of apparatus units (not shown) of the switching network composed of incoming and outgoing trunk circuits, trunk and oce link frames and interfrarne junctors.

Marker circuits, such as marker MKR, control the apparatus units (not shown) ofthe trunk and office link frames through trunk and oflice link connectors, such as connectors TFC and OFC, to establish connections between incoming and loutgoing trunks.

Incoming trunks have access to senders, such as sender SDR, throughincoming trunk circuits and sender links, such as link SL. The trunk to sender connections are established with the aid of. controller circuits, such as controller CL, associated with the sender links. A-sender circuit is used ou each call to receive and register information regarding the location of incoming trunk circuits on trunk link frames, and the called office code and called customer line number. The sender is also arranged to convey all of this information except the called customer line number to a marker through a marker connector, such as connector MC, to enable the marker to perform the necessary translating and control functions required to establish acommunication channel between incoming and outgoing trunksand to prescribe for the sendenthe character of outpulse signaling to be used to control equipment at completing and terminating oliices.

The system is also equipped with circuit equipment for determining the rate treatment for at rate customer calls. The circuit, illustrated in FiG. 2, comprises apparatus units of the incoming trunk circuit, trunk link frame, trunk link connector, marker, marker connector, and ender. As is hereinafter described, this circuit functions to indicate those calls that are Within the flat rate calling area. it also functions to inform the sender of the appropriate charge rate for flat rate customer calls and when operator assistance is not required for identifying the called customer number and when no billing record of a call is required.

Position link circuits, such as circuit PL, are used to interconnect operator position circuits, such as circuit OP, and calling customer lines via a sender, sender link, incoming trunk circuit, incoming trunk, and originating ofdce equipment. An operator attends each position circuit and functions during the processing of an extra charge call to orally obtain calling customer directory number and to manually operate the keys (not shown) of the position circuit to pass that number to a sender for i billing purposes. The functions of the operator position circuit, position link circuits, and of the operator are required only on those customer calls which involve an extra charge and for which a billing record must be made.

The billing and recording facilities are associated With certain senders, sender links, and incoming trunk circuits to record the biiling data derived therefrom for eXtra charge calls.

The cooperation of the various circuit units with one another in aifecting the establishment of a communications channel through the tandem oiice will now be descri ed by tracing a call from a flat rate customer, line served by a local oice which is not equipped with automatic call recording facilities. This call Will be completed to a called customer line served by a terminating oflice Within the flat rate customer calling area.

Referring again to FiG. 1, it is assumed that a call has been originated over theiiatrate customer line FRL served by the originatingofrlce OR and that control equipment (not shown) at office OR is operated to receive and register the calledoice code and called customer line number dialed by the calling party and to thereafter eect seizure of the associated trunk l'.. It is further assumed that this call is directed to the called customer CC. As' is fully described in the previously mentioned Breed et al. patent, when trunk iTK is seized, the related incoming trunk circuit lTC recognizes the seizure and operates to signal the controller Cl.. via the sender link SL to activate the sender link SL to connect the seized trunk ITK to thel senderv SDR. The sender link SL and controller CL, upon activation, proceed to inform the sender SDR of the number of trunk link frame TLFl on which the trunk lTK is located. The sender SDR- then proceeds to register this data.

After the sender link SL and controller` CL have performed these operations, controller CL effects the transmission of a signal to the originating oce GR to. notify equipment (not shown) of that -otlice that the tandem sender SDR is prepared to receive therefrom the pulses that compose the digits of the called ofce coder-.nd called customer line number. Thereafter, the controller CL is released Vand the data is pulsed forward yfrom equipment (not shown) of omce OR over trunk TK through switching apparatus (not shown) of trunk circuit lTC and sender link` SL to registers (not shown) in sender SDR.

Immediately following the registration of the called ofllce code in the sender SDR, the latter circuit is con-V nected to the marker MKB through the marker connector MC and it transfers to the marker MKR the called otlce code and lframe number on which trunk AITC is located.

The marker MKR is equipped with an otlice code trans.- lator circuit which translates the called oiice code and supplies control information required to complete called connections and to determine the call rate treatment. The essential elements of this circuit are shown in FIG. 2 to illustrate the manner in which the rate determining equipment may be connected with equipment of the marker MKR. A detailed disclosure of a translator circuit arrangement suitable for use in the instant embodirent is described in US. latent 2,235,833, issued March 18, 1941, to W. W. Carpenter. As is Adescribed in the latter patent, the translator circuit includes a plurality of route relays each of which supplies separate control information required by the marker MKR to complete call connections to various completing and terminating oices served by the tandem office. In many instances, one or more route relays :are provided in the marker MKl to supply dierent information required to complete call connections betwen different originating otices and one completing or terminating otlce because of the diverse characteristics of equipment at originating offices and the different distances between the latter or'lices and the completing or terminating oices. The translator circuit in the exemplary embodiment of FIG. Z translates the called oli'ice code in a manner not shown in the drawings and grounds one of the code points CP1, CP2, or CP- to complete a circuit for operating an appropriate one of route relays lR1, R2, or R- which supplies the control information. The operate circuits for the route relays extend from ground through the code points CP1, CP2, and CP-, leads cross-connected to the route code points RPF., R132, and RP- and the route relay windings to battery ZBG. Contacts (not shown) of the route relays close circuit paths (not shown) to supply control information pertinent to the outgoing trunk circuits and trunk to be used to establish terminating call connections. Additional information supplied under control of the route relays to the sender SDR for Outpulsing includes the particular type of pulsing (dial, revertive, or multifrequency), the number of digits to be outpulsed, and the speed and signal level of pulse transmission. For purposes of illustrating the functions of the invention, it is assumed that ground potential is connected through the code points CP1 and RPi and the winding of the route relay R1 to battery 2B@ for operating relay Rl to control the establishment of call connections over the outgoing trunk circuits OTC and trunk OTK to the terminating oilice TO.

The translator circuit of FIG. Z also supplies to the rate determining equipment the information which indicates the various completing and terminating offices to which call connections can be established. The manner in which the two circuits cooperate vwith each other is described in the subsequent paragraphs.

The marker MKR is arranged to function with -a maximum of twenty trunk link frames and is provided with a trunk link frame relay to identify each of these frames. Three of these relays, shown in FIG. 2, are designated TFL TF-, and T529; and each identities, respectively, the trunk link frames TLFl, TLFZ-IQ (not shown), and TLFZQ (not shown). These relays are controlled by the trunk link frame register circuit of FIG. 2, which is shown mainly in block diagram `form therein because weh a circuit is well known in the art. For example, it may be similar to the district frame register circuit disclosed in U.S. Paten-t 2,235,803, issued March 18, l94l, to W. W. Carpenter. Therefore, the description or the trunk link frame register circuit is of a general nature `and only those details necessary for complete understanding of the invention are presented. ri`he register circuit of FIG. 2 stores the trunk link frame number transferred thereto, as previously explained, from the sender SDR via the connector MC, and it closes a circuit path whereby the frame relay TF1 is operated to identify the irame TLFl on which appears the incoming trunk circuit ITC. rille obvious operate path for relay TF1 extends from ground in the register circuit through the relay winding to the battery 231. Similar operate paths are used to control the relays TF- and TlZ. Contacts of the relays TF1, TF-, and TF2@ are used to control the operating circuits for the rate treatment relays RTL-2d of FIG. 2 and facilitate the expansion of rate treatment information as is hereinafter described.

Referring again to FIG. l, the marker, under control of the operated route relay Rl, seizes the oliice link frame GLF through the office link connector OLC to select the outgoing trunk circuit OTC and trunk GTK to the called terminating oiilce TO. With knowledge of the trunk link frame involved on ythe instant call, the marker MKR then seizes the frame TLFl through the trunk link connector TLC and proceeds to test the available communication channels for interconnecting the incoming trunk circuit ITC and outgoing trunk OTK. After iinding an available channel therebetween, it effects the operation of switches (not shown) on the trunk and oiiice link frames TLF. and OLP to close through that channel. This channel is extended further by the trunk circuit ITC through the sender link SL to the sender SDR and provides a path for subsequently outpulsing information from the sender SDR to control equipment (not shown) at the terminating oihce TO to establish interconnections between trunk `GTK and the called customer line CCL. After this channel is established, marker MKR passes to the sender SDR by way ot the connector MC, `the route relay infomation regarding `the character of outpulsing to be sent over the established connections.

Before tracing the call further through the system, it is desirable first to review certain assumptions upon which the operation oi the exemplary embodiment of the invention is based. The present embodiment is devised for use with a plurality of trunks extending between the tandem oiirice and various originating otiices. These trunks are terminated at incoming trunk circuits which are proportionately distributed over a maximum of twenty trunk link trames. All incoming trunks and trunk circuits that handle trar'iic trom iiat rate customers entitled to the same rate treatment are located on one trunk link frame and are identified as a ilat rate group. Twenty ilat rate groups are therefore available with one group located on each of twenty trunk link vframes. A group may include trunks and trunk circuits associated with one or more `oiiices lfrom which flat rate customer calls originate.

When any of the trunks and trunk circuits is engaged on a customer call, the trunk circuit is arranged to operate a ilat rate relay in a tandem marker to inform the marker that it and the associated trunk are in a flat rate group on one of twenty trunk link frames. The marker combines this identifying information with the known identity of the trunk link trame on which the engaged trunk circuit appears and operates one or twenty rate treatment relays in the marker to identity the particular at rate group and to determine the terminating oices to which calls are extended from the engaged trunk on a llat rate basis. rlhe operated rate treatment relay cooperates with the otiice code translator circuit in the marker to operate a no-extra charge relay in the marker which signilies when the call is to be completed to an oliice within the calling customer at rate calling area. When it is operated, the latter relay in turn effects the operation of a no-extra charge auxiliary relay in the sender circuit associated with the marker to inform the sender that operator assistance and a charge record are not required for the call. The sender circuit then cancels the operations of the position link `and operator position circuits, and of the billing and recording facilities.

Returning now to the previous description concerned with tracing a call through the system, the further operations of the rate determining circuit will be described with reference to PEG. 2. When the marker MRR seizes the trunk link lframe TLFl, as previously mentioned, a circuit .path is completed for operating the ilat rate relay FR to inform the marker MKR that it is handling a at rate customer call. This circuit pat-h extends from ground through a relay contact (not shown) in the incoming trunk circuit lTC, lead FLl, switch gear (not shown) of the trunk link frame TLFl, lead FLA, switch gear (not shown) of the trunk link connector TLC, lead FL, and the winding of relay FR to battery ZBZ. The lead FLl of the latter circuit path is multipled `from the frame TLFl to all incoming trunk circuits in the same flat rate group to permit each of them to utilize the same circuit path through the frame TLFl, lead FLA, connector RC, and lead FL to operate relay FR when one of these trunk circuits is engaged on a call. Circuit paths, similar to the one illustrated on FiG, 2, may be provided from a flat rate group of incoming trunk circuits '(not shown )on a maximum of nineteen other trunk link trames (not shown), through the latter frames and the trunk link connectors associated therewith to the lead FL multiple for operating the FR relay when a trunk circuit in one of these groups is engaged on a call.

The operation of the relay FR completes a circuit for ai 'i operating one of twenty relays in the marker Mlll which control, as hereinafter explained, the rate treatment to be accordded to customer calls handled by the ilat rate group of incoming trunk circuits located on the frames TLEl-Z-tl. Three of these relays, shown on FiG. 2, are designated RTE, R'l-, and Pel-2S; and each represents, respectively, the dat rate groups on the trunk link frames TLF, TLEE-ELQ (not shown), and TLFZ (not shown). The individual operate circuits for the relays RT-253 extend from ground through the make contact of relay FR, contacts of the trunk link frame iderifying relays TEE-29, and the windings of the Rill-2li relays to battery 253. Locking paths provided for each of the PTl-f/tl relays through the Contact l of the respective relays RTE-Ztl and a make contact of the olf-normal relay N (not shown) to ground to maintain an operated RTl-Z@ relay operated after the marker MKR and trunk circuit are disconnected and relay El?. is released. The operation of the ON relay (not shown) occurs when the marker MKR is connected with the sender and remains operated to control various circuit paths in the marker MKB. and circuits associated therewith until the marker MKR has completed its functions and is released. When the FR relay is actuated during the progress of the instant call, the RTl relay will be operated and locked operated over the aforementioned circuit path. Shortly after relay RTE is vlocked operated, the marker MKR effects the release of the connectors TLC and GLC, and in turn the release of relay FR.

The rate determining circuit employs a rio-extra charge relay NEC, shown on HG. 2, with `its operate winding connected in multiple with the diodes Dl, DE, and D3, and the various contacts of the rate treatment relays .RTL R and PE2-(i to the rate code points RC1, RC2, and RC-. Each o-f the latter code points is connected with the ofiice code translator circuit by means of a separate conductor to the route code points RPl, PE2, and RD- which are associated, respectively, with the code points CP1, CP2, and Cue. As was previously mentioned, the oice code translator circuit supplies the rate determining circuit With the information which indicates the various completing and terminating offices to which call connections can be established from the tandem ofce. This information consists of connecting a ground potential, in accordance with the called office code, to the rate code points RC1, RC2, and RC- via the code points CP1, CP2, CP-, RPl, RPZ, and REL. Each of the rate code points in the illustrtaed embodiment identilies a particular completing or terminating office served by the tandem ofce. The ground potential connectable to the latter code points can be extended through operated contacts of the relays RT, RT-, and RTZQ, the associated diodes Dl, D2, and D-, and the NEC relay Winding to battery i284 to operate relay NEC on those flat rate customer calls Within the flat rate calling area that are completed Without an extra charge that do not require operator assistance or a record of the call to be made. The pattern for operating the relay NEC is established by contacts of relays RTll, RT-, and hat is, contacts of these relays are added in the parallel operate paths for relay NEC extending between tile diodes Dl, D2, and D- and the rate code points lCi, RC2, and RC- to specify the terminating offices Within the llat rate calling area for customer calls served by incoming trunks and trunk circuits in various `ilat rate groups. The diodes D1, D2, and D- are used for isolation purposes between the rate code points and route code points and are poled to prevent back-ups and ialse operations of more than one route relay at a time. The diodes provide a low forward impedance path for operating the relay NEC and high impedance path between a grounded one of the rate codepoints connected with an operated route relay and the other ungrounded rate code points connected to unoperated route relays.

it will be recalled from the foregoing discussion that .asti

ground potential is assumed to be connected to the code points CP1 and RF1 for operating the route relay R1 to enable marker MKB to handle the call being traced through the system. Under this condition, When the relay Rill is operated, as previously explained, the ground potte tial is extended. further from code point Rll over the lead cross-connected to the code point RC1 through the latter point, Contact 2 of relay RTL diode D, and the NEC relay Winding to battery 234 to operate relay l EC and thereby signify that no extra charge is made for this call. Upon operating, relay NEC closes its make Contact to extend ground potential through relay contacts (not shown) of connector MC to the sender SDR the winding of the no-extra charge auxiliary relay NECA of 2 to battery 2B5 to operate relay NECA `which then locks operated through its own make Contact and operated contact of the oil-normal auxiliary relay ONA (not shown) in the sender SDR. The operation of relay ONA (not shown) occurs when the sender SDR is connected with the incoming trunk circuit lTC and remains operated to control various circuit paths` in the sender SDR until the sender SDR has completed its functions -and is released. Contacts (not shown) of relay NECA are utilized, in a manner not shown in the drawings, by the sender SBR to cancel the operation of the position link EL, operator position OP, and the billing and recording facilities on the call in progress.

When the marker MKR has completed the foregoing circuit operations and others, which are not described herein because they are not necessary for an understanding of the invention, the marker MKB and connector MC are released.

Referring again to EEG. l, after the sender SDR has received the last digit of the called customer number from the originating ofce, it immediately operates in accordance with the charging information received from rate determining equipment in the marker MKR to outpulse control signals to the terminating office TO for operating equipment (not shown) thereat to establish call connections yfrom the outgoing trunk UTK to the called customer line CCL. The character of the outpulsed control signals is determined, as previously explained, by the route relay Rl in the marker MKB. Sender SDR outpulses to the terminating office TO Avia switching gear (not shown) of the sender link SL, incoming trunk circuit ITC, trunk link frame TLF-, over interfrarne junctors, office link frame GLF, outgoing trunk circuit OTC, and the outgoing trunlr` OTK.

After transmitting the control signals to the office TO, the sender SDR `signals the incoming trunk circuit lTC to establish connections between the incoming trunk ITK and the communication channel extending through the trunk and orice link frames TLFl and GLF, outgoing trunk circuit OTC, and trunk OTK to the terminating ollice TO. The sender SDR then allows the incoming trunk circuit ITC to assume supervision over the call connections until the conclusion of the cal. The sender and sender link SL are then released.

To' illustrate an additional Way in which the instant invention simplifies procedures for determining flat rate customer charges in the instant centralized call recording system, a brief description will now be given ot the manner in which circuits of the tandem ohlce would normally function on the instant call Without the rate determining equipment. it should be observed from this description that the equipment operations andV operator functions associated with recording the call cata would unduly delay the completion of the call and add to the holding time of other switching equipments because the instant call is within the flat rate calling area and no extra charge is required therefor. This description is based on the assumption that equipment -is not provided in the ofce OR for screening the call to determine whether the terminating otlce TO is within or without the customer flat rate calling area. Anotier assumption is that one trunk facility is used to handle both at rate and extra charge traldc. lt will be recalled from the previous description that, after the last digit of the called customer number was received by the sender SDR from the originating ofhce OR, sender SDR immediately operated, in accordance with the charge information received from the rate determining circuit in the marker MK?. to outpulse control signals to the oliice TO in order to establish call connections from the trunk ITK to the called customer line CCL. When the rate determining equipment is not provided, however, the outpulsing by sender SDR is delayed and the following operations occur. Referring to FIG. 1, the sender SDR signals the position link circuit PL to connect the operator position circuit OP into a talking path to the calling customer by way of equipment (not shown) of the position link PL, sender link SL, trunk circuit ITC, trunk HK, office OR, and the line PRL. The operator attending the position OP is then given a Zip tone as 4an indication to make an oral request for the calling customer directory number from the calling party. Following the receipt of this directory number, the opertaor manually operates a key mechanism (not shown) of the position circuit -OP in order to transmit that number to the sender SDR via the position `link PL. After the operator Ihas keyed the last digit of the number, the connection between the position circuit i and the sender SDP` is released. The sender SDR then associates itself with the billing and recording fac ities and informs it of the calling and called customer numbers. The billing and recording Ifacilities then operate automatically, in a manner described in the aforementioned l. N. Breed et al. patent, to malte a record of the telephone call details. Meanwhile, the sender SDR proceeds to transmit the appropriate control signals to the oilice TO to establish, as hereinbefore explained, call connections between trunk OTK and the called customer line CCL. The call connections are then completed in a manner described in the previous paragraphs.

lt to be understood that the above-described arrangements are illustrative of tbe application of tbe principles of this invention. In light of this teaching, it is apparent that numerous other arrangements may be devised by those skilled in the art without departing from the spirit and scope ofthe invention.

Vihat is claimed is:

1. In a telephone system, an originating orice serving the tiat rate customer line, a tandem oiice, a trunk extending between said oflices, means in said originating otce responsive to calls on said line for extending said calls from said line over said trunk to said tandem oice, a plurality of terminating oilices each baving an identifying olice code, means in said originating olce operative subsequent to the extension of said calls for transmitting over said trunk signals representing the desired terminating office code for each of said calls, means in said tana oliice operable for interconnecting said trunk wit a number of said terminating oilices on a flat rate basis and with all of tire other terminating oilices on an extra charge rate basis, an equipment frame in said tandem office, and circuit means in said tandem oice associated with said trunk on said frame and operative in response to the extension of said calls over said trunk for operating said interconnecting means to interconnect said trunk and said terminating offices, said interconnecting means comprising means responsive to the operation of said circuit means for identifying said trunk, means controlled by the operation of said circuit means for identifying said frame, means responsive on each call to translate said office code signals, and means jointly controlled by said frame identifying means, by said trunk identifying means, and by said translating means to determine said terminating offices to which interconnections are established on a at rate basis.

2. In a telephone system, an originating office serving a flat rate customer line, a tandem oliice, a trunk extending between said offices, means in said originating oflice responsive to calls on said line for extending said calls from said line over said trunk to said tandem office, a plurality of terminating offices, means in said tandem office operable for interconnecting said trunk with a number of said terminating offices on a flat rate basis and with all of the other terminating offices on an extra charge rate basis, circut means in said tandem odice associated with said trunk and operative in response to tbe extension of said calls over said trunk for operating said interconnecting means to interconnect said trunk to said terminating olices, means in said tandem oiice operable under control of said interconnecting means for recording charge data concerning said interconnections, and means in said interconnecting means controlled by said circuit means for rendering said recording means operative only for interconnections established on an extra charge rate basis.

3. In a telephone system, an originating ofce serving a flat rate customer line, a tandem olii e, a trunk extending between said offices, means in said originating otlice responsive to calls on said line for extending said calls rom said line over said trunlt to said tandem olrce, a plurality of terminating oiices, means in said tandem ofce operable for interconnecting said trunk with a number of said terminating ollices on a ilat rate basis and with all of tbe other terminating offices on an extra charge rate basis, an equipment frame in said tandem ofiice, circuit means in said tandem office associated with said trunk on said frame and operative in response to tbe extension of said calls over said trunk for operating said interconnecting means to interconnect said trunk and said terminating offices, and means in said tandem office operable under control of said interconnecting means for recording charge data concerning said interconnections, said interconnecting means comprising means responsive to tbe operation of said circuit means for identifying said trunic, means controlled by tne operation of said circuit means for identifying said frame, means jointly controlled by said trunk identifying means and by said trame identifying means for determining said terminating oices to which said interconnections are established on a at rate basis, and means controlled by said determining means for rendering said recording means operative only for interconnections establisbed on an extra charge rate basis.

4. in a telephone system, an originating oice serving a dat rate customer line, a tandem ofce, a trunk extending between said oriices, means in said originating otiice responsive to calls on said line for extending said calls from said line over said trunl: to said tandem oiiice, a plurality of terminating oces eacb hav an identifying ofiice code, means in said originating omce operable subsequent to the extension of said calls for transmitting over said trunk signals representing any said office codes, means in said tandem office operable for interconnecting said trunk with a number of said terminating olices on a tlat rate basis and with all of the other terminating orices on an extra charge rate basis, an equipment frame in said tandem ofrce, circiut means in said tandem office associated with said trunk on said frame and operative in response to the extension of said calls over said trunlt for operating said interconnecting means to interconnect said trunk and said terminating orlices, and means in said tandem office operable under control of said interconnecting means for recording charge data concerning said interconnections, said interconecting means comprising means responsive to the operation of said circuit means for identifying said trunk, means controlled by the operation or said circuit means for identifying said frame, means operative on each call for translating said transmitted office code signals, means jointly controlled by said trunk identifying means, by said frame identifying means, and by said translating means for determining said terminating oices to which interconnections are established on a flat rate basis, and means controlled by said determining means for rendering said il ll recording means operative only for interconnections established on an extra charge rate basis.

5. ln a telephone system, a tandem oilice, a trunk for serving flat rate and extra charge rate calls incoming to said tandem oiice, a plurality of terminating oices each having an identifying oiiice code, means in said tandem office connectable with saidttrunk on each call for registering signals representing tile desired terminating oiice code, an equipment frame in said tandem oice, circuit means in said tandem oilice associated with said trunk on said frame and operative in response to each call on said trunk for interconnecting said trank and said registering means, and a control circuit m said tandem oliice including means for trmslating or'ice code signals registered in said registering means, means operabie for interconnecting said trunk with a number of said terminating offices on a dat rate basis and with all of the other terminating oices on an extra charge rate basis, means controlled by said translating means for operating said interconnecting means to interconnect said trunk with tbe desired terminating oilice, and jointly controlled by said translating means and by sai circuit means for determining the appropriate one of said rates :for said interconnections, said determining means comprising means responsive to the operation of said circuit means tor identifying said trunk, means controlled by tne operation of said circuit means for identifying said frame, means jointly controlled by said trunk identifying means and by said frame identifying means for spec1 ying said terminating oices with which said trunk is interconnected on a iqiat rate basis, and means jointly controlled by said translating means and by said specifymg means to signify tbe appropriate one of said rates for said interconnections.

6. In a telephone system, a tandem oilice, a trunk for serving dat rate and extra charge rate calls incoming t said tandem office, a plurality of terminating oilices each having an identifying oiiice code, means in said tandem olli-ce connectable with said trunk in response to calls tnereon for registering signals representing said olce codes, ari equipment frame in said tandem orl'lce, circuit means in said tandem otlce associated with said tmnli on said frame and operative in response to calls on said trunk for interconnecting said trunk and said registering means, means in said tandem oflce associable with said trunk and said circuit means and operable for recording charge data derived therefrom concerning said calls, and a control circuit in said tandem office including means for translating ofce code signals registered iri said registering means, means controlled by said translating means for controlling the interconnection of said trunk with a number of said terminating otiices on a ilat rate basis and with all of the other terminating oiiice on an extra charge rate basis, and means jointly controlled by said translating means and by said circuit means for determining the appropriate one of said rates for said interconnections, said determining means comprising means responsive to tbe operation of said circuit means for identifying said trunk, means controlled by the operation of said circuit means for identifying said frame, means jointly controlled by said trunk identifying means and by said frame identifying means for specifying said terminating ofces with which said trunk is interconnected on a i'lat rate basis, means jointly controlled by said translating means and by said specifying means to signify tbe appropriate one of said rates, and means controlled by said signifying means to render said recording means operative only for interconnections established on 'in extra charge rate basis.

7. In a telephone system, an originating oice serving a lat rate customer line, a tandem otiice, a trunk extending between said omces, means in said originating oice responsive to ordis on said line for extending said calls from said line over said trunk to said tandem office, a plurality oi terminating c-iices each 1saying an identifying office code, eans in said originating oilce operative subsequent to die extension oi said calls over said trunk for connection of said trunk with a number of said terminat-` ing orlces on a flat rate basis and with all of the other terminating otlces on an extra charge rate basis, and means jointly controlled by said translating means and by said circuit means for determining the appropriate rate for eac'n of said interconnections.

8. In a telephone system, an originating otlice serving a flat rate customer line, a tandem oflice, a trunk extendbetween said oce, means in said originating oiice responsive to calls on said line for extending said calls from said line over said trunk to said tandem office, a plurality of terminating oices each having ari identifying oce code, means in said originating ollice operative subsequent to the extension of said calls over said trunk for transmitting over said trunk signals odice codes, means in said tandem oice connectable with said trunk for registering oiiice code signals transmitted thereover, an equipment frame in said tandem office, circuit means in said tandem oi'ice associated with said trunk on said frame and operative in response to the extension of said calls over said trunk for interconnecting said trunk and said registering means, and a control circuit in said tandem oilice including means for translating olllce code signals registered in said registering means, means controlled by said translating means for controlling the interconnection of said trunk with a number of said terminating oces on a flat rate basis and with all of 'die other terminating offices on an extra charge rate basis, and means jointly controlled by said translating means and by said circuit means for determining the appropriate one of said rates for said interconnections, said determining means comprising means responsive to tbe operation of said circuit means for identifying said trunk, means con-V trolled by the operation'ot said circuit means for identifying said frame, means jointly controlled by said trunk identifying means and by said framev identifying means for specifying said terminating oiiices with which said trunk is interconnected on a ilat rate basis, and-means jointly controlled by said translating means and by said specifying means to signify the appropriate one of said rates for said interconnections.

9. ln a telephone system, an originating ndice serving a tlat rate customer line, a tandem otrlce, a trunk extending between said oilices, means in said originating orTice responsive to `calls on said line for extending said calls from said line over said trunk to said tandem otlice, a plurality of terminating ofces eac'n having identifying cnice code, means in said originating oiice operative subsequent to the extension of said calls over said trunk for transmitting over said trunk signals representing said ofce codes, means in said tandem ofrice connectable with k said trunk for registering oilce code signals transmitted there-over, an equipment frame in said tandem cnice, circuit means in said tandem ofce associated with said trunk on said frame and operative in response to tbe extension or" said calls over said trnnlr for interconnecting said trunk and said registering means, means in said tandem ofice associable with said truniL and said circuit means and operable for recording cbarge data derived therefrom concerning said calls, and a control circuit in :said tandem olice including means for translating oilice code signals registered in said registering means, means controlled by said translating means for controlling tb interconnection of said trani; with a number of said terminating oii'ices on a ilat rate basis with all of tbe representing saidV other terminating oices on an extra charge rate basis, and means jointly controlled by said translating means and by said circuit means for eterrnining the appropriate one of said rates for said interconnections, said determining means comprising means responsive to the operation of said circuit means for identifying said trunk, means controlled by the operation of said circuit means for identifying said frame, means jointly controlled by said trunk identifying means and by said frame identifying means for specifying said terminating oices with which said trunk is interconnected on a ilat rate basis, means jointly controlled by said translating means and by said specifying means to signify the appropriate one of said rates, and means controlled by said signifying means to render said recording means operative only for interconnections established on an extra charge rate basis.

10. In a telephone system, a switching otlice, a plurality of incoming trunk-s each used for serving both tiat rate and extra charge rate calls, a plurality of outgoing trunks, means in said ofce operable for interconnecting said incoming trunks with a number of said outgoing trunks on a flat rate basis and Wit'n all of the other outgoing trunks on an extra charge rate basis, a plurality of equipment frames in said office each identified with a specilic rate treatment, each ot said incoming trunks that serve calls entitled to the same rate treatment terminated on said frame identiiied with said treatment, and circuit means on said frames associated with said incoming trunks and operable in response to both r'lat rate and extra charge rate calls on any selected incoming trunk for operating said interconnecting means to interconnect said selected trunk with any of said outgoing trunks to the called destination desired by the caller, said interconnecting means comprising means responsive to the operation or said circuit means for identifying said frame on which the selected trunk is terminated, means for identifying said selected trunk, and means joint.y controlled by said frame identifying means and said trunk identifying means for determining said outgoing trunks with which interconnections may be established on a at rate basis.

ll. In a telephone system, a switching otiice, a plurality of incoming trunks each used for serving both fiat rate and extra charge rate calls incoming to said oilice, a plurality of terminating oiiices each having an identifying oiiice code, means in said switching oice operable for interconnecting said trunks v/itn a number of said terminating oices on a iiat rate basis and with all of the other terminating oiices on an extra charge rate basis, a plurality of equipment frames in said switching oce each identiiied with a speciiic rate treatment, each of said trunks that serve calls entitled to the same rate treatment terminated on said frame identiiied with said treatment, and circuit means associated with said trunks on said vframes and responsive to fiat rate and extra charge rate calls on any selected one or said trunks for operating said interconnecting means to interconnect said selected trunk with any of said called terminating offices, said interconnecting means comprisin.U means controlled by said circuit means for identifying said frame on which the selected trunk i-s terminated, means for identifying said selected trank, means responsive to each call on said selected trunk for translating said code of the terminating oiiice with which said selected trunk is interconnected, and means jointly controlled by said frame identifying means and said trunk identifying means and responsive to said code translation for determining Whether said interconnection may be established on a ilat rate basis.

l2. in a telephone system according to claim 1'1 the combination further comprising means operable on each call served by said trunks for recording charge data concerning saidinterconnections, and means controlled by said determining means for rendering said recording means operative only for interconnections established on an extra charge rate basis.

References Qited in the tile of this patent 

1. IN A TELEPHONE SYSTEM, AN ORIGINATING OFFICE SERVING THE FLAT RATE CUSTOMER LINE, A TANDEM OFFICE, A TRUNK EXTENDING BETWEEN SAID OFFICES, MEANS IN SAID ORIGINATING OFFICE RESPONSIVE TO CALLS ON SAID LINE FOR EXTENDING SAID CALLS FROM SAID LINE OVER SAID TRUNK TO SAID TANDEM OFFICE, A PLURALITY OF TERMINATING OFFICES EACH HAVING AN IDENTIFYING OFFICE CODE, MEANS IN SAID ORIGINATING OFFICE OPERATIVE SUBSEQUENT TO THE EXTENSION OF SAID CALLS FOR TRANSMITTING OVER SAID TRUNK SIGNALS REPRESENTING THE DESIRED TERMINATING OFFICE CODE FOR EACH OF SAID CALLS, MEANS IN SAID TANDEM OFFICE OPERABLE FOR INTERCONNECTING SAID TRUNK WITH A NUMBER OF SAID TERMINATING OFFICES ON A FLAT RATE BASIS AND WITH ALL OF THE OTHER TERMINATING OFFICES ON AN EXTRA CHARGE RATE BASIS, AN EQUIPMENT FRAME IN SAID TANDEM OFFICE, AND CIRCUIT MEANS IN SAID TANDEM OFFICE ASSOCIATED WITH SAID TRUNK ON SAID FRAME AND OPERATIVE IN RESPONSE TO THE EXTENSION OF SAID CALLS OVER SAID TRUNK FOR OPERATING SAID INTERCONNECTING MEANS TO INTERCONNECT SAID TRUNK AND SAID TERMINATING OFFICES, SAID INTERCONNECTING MEANS COMPRISING MEANS RESPONSIVE TO THE OPERATION OF SAID CIRCUIT MEANS FOR IDENTIFYING SAID TRUNK, MEANS CONTROLLED BY THE OPERATION OF SAID CIRCUIT MEANS FOR IDENTIFYING SAID FRAME, MEANS RESPONSIVE ON EACH CALL TO TRANSLATE SAID OFFICE CODE SIGNALS, AND MEANS JOINTLY CONTROLLED BY SAID FRAME IDENTIFYING MEANS, BY SAID TRUNK IDENTIFYING MEANS, AND BY SAID TRANSLATING MEANS TO DETERMINE SAID TERMINATING OFFICES TO WHICH INTERCONNECTIONS ARE ESTABLISHED ON A FLAT RATE BASIS. 